CGI Environment Variables
- Variable: Output for your session on this system
- A brief description of the variable.
- Auth_Type:
- The authentication method used to validate a user.
- Content_Length:
- The length of the data (in byes or the number of characters) passed to the CGI program through standard input.
- Content_Type:
- The MIME type of the query data, such as "text/html".
- Date_local:
- Current date and time in the local time zone.
- Date_GMT:
- Current date and time in GMT.
- Document_Name:
- The current file.
- Document_Root:
- The directory from which Web documents are served.
- Document_URI:
- Virtual path to the file.
- Gateway_Interface:
- The revision of the Common Gateway Interface that the server uses.
- HTTP_Accept:
- A list of the MIME types that the client can accept.
- HTTP_From:
- The email address of the user making the request. Most browsers do not support this variable.
- HTTP_Referer:
- The URL of the document that the client points to before accessing the CGI program.
- HTTP_User_Agent:
- The browser the client is using to issue the request.
- Last_Modified:
- Last modification date and time for current file.
- Path_Info:
- Extra path information passed to a CGI program.
- Path_Translated:
- The translated version of the path given by the variable PATH_INFO.
- Query_String:
- The query information passed to the program. It is appended to the URL with a "?".
- Query_String_Unescaped:
- Undecoded query string with all shell metacharacters escaped with "\".
- Request_Method:
- The method with which the information request was issued.
- Remote_Addr:
- The remote IP address of the user making the reqest.
- Remote_Host:
- The remote hostname of the user making the request.
- Remote_Ident:
- The user making the request. This variable will only be set if NCSA IdentityCheck flag is enabled, and the
client machine supports the RFC 931 identification scheme (identd).
- Remote_User:
- The authenticated name of the user.
- Script_Name:
- The virtual path (e.g., /cgi-bin/program.pl) of the script being executed.
- Server_Name:
- The server's hostname or IP address.
- Server_Port:
- The port number of the host on which the server is running.
- Server_Protocol:
- The name and revision of the information protocol the request came in with.
- Server_Software:
- The name and version of the server software that is answering the client request.
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HTML Syntax:
-
<!--#echo var="VARIABLE_NAME"-->
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Example:
-
-
Suppose we want to attempt to print out the email address of the current user. The code would look something like:
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Your email address is <!--#echo var="REMOTE_IDENT"-->@<!--#echo var="REMOTE_HOST"-->.
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That line will print out:
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Your email address is @.
Most of the information in this table came from CGI Programming on the World Wide Web by Shishir Gundavaram.